The Gordon Research Conference on Environmental Sciences: Water is the preeminent conference on aquatic environmental science as a whole. The 25th conference by this name will be held 22-27 June 2014 at the Holderness School near Plymouth, NH. The conference will bring together 180 participants in an informal setting for a program of invited, plenary talks by established and emerging researchers who are doing the most innovative and significant research on diverse aspects of environmental aquatic science. The 2014 conference theme is Environmental Sciences in a Human-Impacted World. Recent attention to human-impacted aquatic systems have highlighted key differences that limit the extent to which contaminant fate and toxicology can be predicted in aquatic systems subject to human alterations. This challenge will be addressed in sessions that range from contaminant fate, to water treatment, human and ecosystem health, and science/risk communication. Historically, the conference has had many sessions that emphasize ecotoxicology, but growing concern about emerging contaminants has created demand for more sessions that address the complexity of chemical toxicity in human systems. In 2014, the investigators are planning to focus some of the talks related to human health into an evening session with the theme Environmental Epigenetics. Two speakers and a discussion leader are being selected to provide cutting-edge science perspectives on toxicological risk to humans posed by exposure to environmental contaminants. This application requests funding to support the registration and travel costs for these three participants. Funding for other parts of the conference program will be mainly from the Environmental Engineering Program of the National Science Foundation and the Gordon Research Conferences organization. The aims of this request are four-fold: (1) Specifically, to assemble the highest caliber researchers for a session that will advance a key frontier in environmental health sciences. (2) More generally, to stimulate greater integration between the environmental health sciences and other disciplines of environmental science and engineering. (3) Foster a multidisciplinary community of researchers that is marked by creative collaborations to solve environmental problems. (4) Encourage diversity in this community with respect to gender, race, nationality, and other categories of less well-represented groups.